Leading-in conductor



Dec. 231'1941.

G. A. FREEMAN LEADING-IN CONDUCTOR Filed Jan. 2, 1941 INVENTOR G'JYP FEM/71V B W A- ORNEY Patented Dec. 23, 1941 U IT-so STATE LEADING-IN co'N Uc'roR George A. l reemam East Orange, N. 5., as signor v v to Westinghouse Electric & Manufacturing Pennsylvania Company, East Pittsburgh, 2a., a corporation of Application January 2, 1941; Serial No. 372,723 7 Claims; (01.176-12'6) The present invention relates to leading-in conductors or stem leads for electric energy translation devices, such asincandescent lamps; high pressure'discharge amps, and radio tubes, which i are hermetically sea ed in the walls of vitreous envelopes.

It is-not uncommoni this art to support what is termed the mount, comprising the electrode assembly or filaments, entirely by the leadingin conductors which are sealed into the stem press. Since the mount is of considerable weight, a substantial strain is thus imposed upon the conductors at the point of seal with the vitreous stem press. ,This has heretofore required costly packing to prevent breakage in shipment'due to vibration or shocks. ing fabrication the stem must necessarily be subjected to a temperature sufhciently high to soften the vitreous material of which the stem is composed, which has a tendency to anneal the metal heretofore employed for the leading-in conductors. It is accordingly an object. of the presentinvention to provide a leading in conductor for electric energy translation devices, such as incandescent electric lamps and the .like, which. readily forms an hermetic seal with the vitreous Moreover, durpair of leading-in-conductors 8 and 9 of a matehardened at the temperatures to which the stem is subjected during fabrication.

Another object of the present invention is' the provision of a leading-in conductor for electrical energy translation devices. which readily forms an hermetic seal with either hard or soft glass ,and which is not detrimentally affected by the temperatures employed in fabrication of the ste m press. 7

A further object of the present invention is the provision of a leading-in conductor for 'electric energy translation devices comprising an alloy of the precipitation hardening type which readily forms an hermetic seal with the vitreous envelope material and hardens at. a temperature within the softening range of the vitreous envelope material.

Still further objects of the present invention will become obvious to those skilled in the a'rt by in: r

The sole figure is an elevational view of an electric energy translation device in the form of a high pressure mercury discharge lamp provided with leading-in conductors in accordance with the present invention.

reference to the accompanying drawing where- Referring now to the drawing in detail. the device as shown comprises an enclosing envelope 5 ofsuitable vitreous material, such as hard or soft glass or-the like, transparent to light, and if desired it may be of quartz or other ultra-violet pervious material.-- Appropriately secured to the envelope is .a basefi of the usual type to enable the devic'eto be screwed into a. socket. 1

-The envelope 5 is provided with a reentrant stem. press 1 to which is hermetically sealed a as quartz orthe like, and provided with the customary electrodes for sustaining a discharge through the gaseous medium within the envelope I- 4.,- In addition, a pair of metallic shields l5 and; it are carried by the bridges adjacent the supported ,ends of the lamp 13 for the purpose of conserving heat and preventing condensation of the gaseous medium within the envelope H.

.The lamp electrodes are connected to the leading-in conductors 8 and 9 by flexible connections 11 and I8, and for starting purposes an impedance device I9 is connected between the leading-in conductor 8 and the customary starting electrode 20, as shown. From the-foregoing it can be appreciated that the structure supported by the leading-in conductors and constituting what is customarily called the mount is of appreciable weight, which places a substantial strain upon the leading-in conductors 8 and 9, particularly at the point of seal thereof with the stem press I.

Heretofore, alloys employed for leading-in conductors have rpo'ssessed the disadvantage that they become soft when heated to the temperatures necessary in stem making because of the anneal.- ing efiect. Such disadvantage is eliminated in the present invention by the provision of leadingin conductors formed of what are known as alloys of the precipitation hardening type. The theory of such alloys is that the degree of solution of one metal into the other is controlled'by heat treatment. By heating 'to comparatively high temperature and quenching in cold water, a

formed of approximately 98% copper and containing about 2% beryllium which hardens at a temperature of approximately 275 .0. .Both of these alloys as drawn are soft and in this condition are made into leads.

Next, the stem press I, if of hard-glass, is formed by sealing the leading-in conductors thereto after which the leads are bent into the desired configuration; The stem press being thus completed and assuming the leading-in conductors 8 and 9 are of nickel-titanium carbide alloy, the stem press is subjected to a temperature of approximately 500 C. for several. hours.- Since this temperature is well below the softening temperature of hard glass, quartz and the like (600 C. and above), the leading -in conductors 8 and 9 are accordingly hardened. If preferred, the leading-in conductors 8 and 8 may be hardened after shaping and prior to sealing-in the stem press, since the fusion temperature of hard glass of 600 C. would have no softening eflect on the previously hardened conductors.

On the other hand, if the stem press I is of soft glass which has a fusion temperature of approximately 500 C. it may be preferable to employ the copper-beryllium alloy since the conductors 8 and 9 can be hardenedat a much lower temperature of 275 C. and in a much shorter period of time than in the case of the several hours required for the nickel-titaniumcarbide alloy. However, it is just as feasible to employ the latter alloy with soft glass or the copperberyllium alloy with'hard glass, inasmuch as temperature affects the alloys only to the point of maximum hardness: and .once' this is reached,

higher temperatures have no effect since these precipitation hardening alloys can be annealed only by quenching from a high temperature.

In addition to the characteristics of readily forming an hermetic seal with either hard or soft glass and of being hardened by heat treatment, these precipitation alloys are quite resilient, thus allowing the mount to spring momentarilywhen subjected to shock and avoiding the possibility of stem glass breakage, after which the mount returns to its original position.

It thus becomes obvious to those skilled in the art that a leading-in conductor for electric energy translation devices is herein provided in which such conductor not only forms an hermetic seal with glass, but is hardened right down to the stem press at the point where greatest strength is required. Moreover, by the use of precipitation hardening alloys'which can be readily hardened at a temperature below the softening temperature of either hard or soft glass, the leading-in conductors can be hardened either after stem making and bending, or prior to sealing-in to the stem, whichever is preferred.

Although one embodiment of the present invention is herein shown and described, it is to be understood that other modifications thereof may be made without departing from the spirit and scope of the appended claims.

I claim:

1. The method of making a leading-in conductor for" electric energy translation devices which comprises forming such conductor of a soft precipitation hardening alloy, heating the conductor thus formed to a high temperature for a period of time exceeding one hour to cause the metals of the alloy to come out of solution and harden the leading-in conductor, and sealing the conductor to the wall of a vitreous envelope.

2. The method of making a leading-in conductor for electric energy translation devices which comprises sealing a leading-in conductor of a soft precipitation hardening alloy into a wall of a vitreous envelope, and thereafter heating the envelope wall together with its sealed leading-in conductor to a temperature'below the softening temperature of the'vitreous envelope wall but at a temperature sufficiently high and for a period of time sufficient to cause the metals of the alloy to come 0 t of solution and the leading-in conductor to come hardened particularly at the point of greatest stress adjacent the seal.

3. The method of making-a leading-in conductor for electric energy translation devices which comprises sealing a leading-in conductor of a soft precipitation hardening alloy into a vitreous stem press, bending the conductor to the desired configuration, and heating the vitreous stem press thus formed to a temperature sufilciently high and for a period of time sufficient to cause the metals of said alloy to come out of solution and the leading-in conductor to become hardened particularly at the point of greatest stress adjacent the seal, and below the softening temperature of the vitreous stem press.

4. The combination with an electric energy translation device provided with a vitreous envelope having-a mount therein, of a leading-in conductor comprising a precipitation hardening alloy hermetically sealedto said envelope and hardened at the point of maximum stress adjacent said seal by heat treatment to a'temperature below thesoftening temperature of the vitreous envelope to form a resilient support for said mount.

5. The combination with an electric energy translation device provided with a vitreous envelope having a mount therein, 01' a leading-in conductor comprising a precipitation hardening alloy consisting of at least two metals out of solution, to harden said alloy, and hermetically sealed to saidvitreous envelope to form a resilient support for said mount. v

6. The combination with an electric energy translation device provided with a. vitreous envelope having a mount therein, of a leading-in conductor comprising a precipitation hardening alloy consisting of approximately 98.5% nickel and the remainder substantially titanium carbide hermetically sealed to said vitreous envelope and hardened adjacent said seal to form a resilient support for said mount.

7. The combination with an electric energy translation device provided with a vitreous envelope having a mount therein, of a leading-in conductor comprising a precipitation hardening alloy consisting ,of approximately 98% copper and'the remaining 2% being beryllium hermetically sealed to said vitreous envelope and hardened adjacent said seal to form a resilient support for said mount.

GEORGE A. FREEMAN. 

